Hello,

If you are looking for a or just one book for all of OOP that would be hard to do.

I personally like the "Agile Principles and Practices in C#" by Robert Martin.

There is a book from Craig Larman (I own the second edition) that is also considered very good "Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and Iterative Development"

 Also very good books (probably more for the intermediate to advanced developers)

 "Refactoring: Improving the Design of Existing Code" by Martin Fowler.

and "Patterns of Entersprise Application Architecture" by Martin Fowler

Hope this helps

regards,

G

Now if you are looking into more entry level books about OOP, there are pleanty.